Browsing by Author "Bobeica, Valentin"

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    CLOSED-CYCLE INTENSIFIED TECHNOLOGY FOR SUSTAINABLE BIOCHEMICAL PRODUCTION OF ALTERNATIVE FUELS FROM AGRICULTURAL WASTES
    (Academia de Ştiinţe a Moldovei, 2017) Covaliova, Olga; Covaliov, Victor; Bobeica, Valentin; Nenno, Vladimir; Duca, Gheorghe
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    EFFECTS OF AMARANTHS’ SEEDS ON DEHYDROGENASE ACTIVITY AND GASES EMISSION IN METHANOGENIC BIOREACTORS
    (CEP USM, 2015) Covaliov, Victor; Senicovscaia, Irina; Nenno, Vladimir; Bobeica, Valentin; Covaliova, Olga
    The influence of amaranths‘ seeds as the source of squalene on the dehydrogenase activity and efficiency of methane production were investigated in methanogenic bench-scale (5000 ml) bioreactors used to treat the mixture of distillery wastes and farmyard manure. The adding of amaranth seeds to the methanogenic bioreactor has an inhibitory effect on the dehydrogenase activity and stimulates the process of methanogenesis. Dehydrogenase activity decreased with the increase of doses of squalene and its trend had a close connection with doses (R2 =0.77-0.78). The methane content in the total amount of gases is 65.3-71.3% in a bioreactor with the additive of amaranth seeds in a dose of 50 mg l-1, which is 22.1% higher than in the the control bioreactor without additives. The increase in squalene concentration higher than 0.0005% is not rational because its stimulating effect on the methanogenic process decreases. Anaerobic digestion of alcohol distillery industry wastes with manure is a complex nonlinear time-varying microbiological process. Dehydrogenase activity trends in the experiment are described by the power function for 5 hours observations and by the logarithmic function for 120 hours of observations. Trends of CH4 are described by the polynomial function in all periods of testing. Correlation coefficients are 0.37 and 0.70 for CH4 after 5 and 120 hours of the anaerobic digestion. Dehydrogenase activity is in the close negative connection with the amount of gases, including methane. Correlation analysis between dehydrogenase activity and the release of gases has revealed the moderate and strongly negative link during 24 hours after the start of the experiment.
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    A NEW METHOD OF CYANCOBALAMIN (VITAMIN B12) PRODUCTION AND ITS PRACTICAL USES
    (Academia de Ştiinţe a Moldovei, 2015) Covaliova, Olga; Covaliov, Victor; Duca, Gheorghe; Nenno, Vladimir; Bobeica, Valentin
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    NEW USES OF BIOACTIVE PHYTOCOMPOUNDS DEPENDING ON MOLECULAR STRUCTURE
    (Academia de Ştiinţe a Moldovei, 2015) Bobeica, Valentin; Covaliov, Victor; Ivancic, Albert; Nenno, Vladimir; Covaliova, Olga